title: Polysaccharides isolated from Açaí fruit induce innate immune responses.
abstract: The Açaí (Acai) fruit is a popular nutritional supplement that purportedly enhances immune system function. These anecdotal claims are supported by limited studies describing immune responses to the Acai polyphenol fraction. Previously, we characterized γδ T cell responses to both polyphenol and polysaccharide fractions from several plant-derived nutritional supplements. Similar polyphenol and polysaccharide fractions are found in Acai fruit. Thus, we hypothesized that one or both of these fractions could activate γδ T cells. Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures. To characterize the immune response to Acai polysaccharides, we fractionated the crude polysaccharide preparation and tested these fractions for activity in human PBMC cultures. The largest Acai polysaccharides were the most active in vitro as indicated by activation of myeloid and γδ T cells. When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production. These results define innate immune responses induced by the polysaccharide component of Acai and have implications for the treatment of asthma and infectious disease.
authors.affiliation: Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America.
authors.forename: Jeff
authors.initials: J
authors.lastname: Holderness
authors.forename: Igor A
authors.initials: IA
authors.lastname: Schepetkin
authors.forename: Brett
authors.initials: B
authors.lastname: Freedman
authors.forename: Liliya N
authors.initials: LN
authors.lastname: Kirpotina
authors.forename: Mark T
authors.initials: MT
authors.lastname: Quinn
authors.forename: Jodi F
authors.initials: JF
authors.lastname: Hedges
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jutila
mesh_terms: D000818:Animals; D028023:Arecaceae / Q000737:chemistry*; D002417:Cattle; D002478:Cells, Cultured; D005638:Fruit / Q000737:chemistry*; D019673:Genes, T-Cell Receptor alpha; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics; D010636:Phenols / Q000494:pharmacology; D011134:Polysaccharides / Q000302:isolation & purification* / Q000494:pharmacology*; D051197:Toll-Like Receptor 4 / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D010636:Phenols; D011134:Polysaccharides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4